Stoke are hoping Mamady Sidibe has avoided a serious injury after he was stretchered off prior to Monday's reserve clash at Aston Villa.The Mali forward twisted his left knee during the warm-up at Villa Park and will undergo tests on Tuesday after leaving the ground on crutches.Sidibe has only recently returned from two-and-a-half months on the sidelines, having hyper-extended the same knee against Fulham in December.Reserve team boss Mark O'Connor told The Sentinel: "Mama has twisted his knee. He went over and was in a lot of pain."I don't think anybody touched him, he just went over. I saw him after and he seemed a little better in himself, but once we get him looked at, we will know more."It could be that this is just a scare and he is fine by the end of the week. I honestly don't know, but I am just hoping he is all right."